In 1832, Belgian physicist Joseph Plateau and his sons
introduced the phenakistoscope ("spindle
viewer"). It was also invented independently in the
same year by Simon von Stampfer of Vienna, Austria, who called
his invention a stroboscope. Plateau's inspiration had come
primarily from the work of Michael Faraday and Peter Mark Roget (the compiler of
Roget's Thesaurus). Faraday had invented a device he
called "Michael Faraday's Wheel," that consisted of
two discs that spun in opposite directions from each
other. From this, Plateau took another step, adapting Faraday's wheel
into a toy he later named the phenakistoscope.

How it works:

The phenakistoscope uses the persistence of motion principle
to create an illusion of motion. Although this principle
had been recognized by the Greek mathematician Euclid and later
in experiments by Newton, it was not until 1829 that this
principle became firmly established by Joseph Plateau.

The phenakistoscope consisted of two discs mounted on the
same axis. The first disc had slots around the edge, and
the second contained drawings of successive action, drawn around
the disc in concentric circles. Unlike Faraday's Wheel,
whose pair of discs spun in opposite directions, a
phenakistoscope's discs spin together in the same
direction. When viewed in a mirror through the first
disc's slots, the pictures on the second disc will appear to
move.

After going to market, the phenakistoscope received other
names, including Phantasmascope and Fantoscope (and
phenakistiscope in Britain and many other countries). It was
quite successful for two years until William George Horner
invented the zoetrope, which offered two improvements on the
phenakistoscope. First, the zoetrope did not require a
viewing mirror. The second and most influential
improvement was that more than one person could view the moving
pictures at the same time.